The waterfall in the foreground here is Kirkjufellsfoss, named after Kirkjufell, the mountain in the background.

If you google "Kirkjufellsfoss" and look at the images returned you will see this is an extremely common viewpoint. Getting both the waterfall and mountain into the frame requires moving down to the level of the stream but when I was there the rocks were coated with ice and I didn't feel like chancing it! So I set up on the edge and took two shots to make a 'vertorama' and get the whole scene in one image.